/* 全局重置和基础设置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #6366f1;
    --secondary-color: #8b5cf6;
    --accent-color: #ec4899;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: #475569;
    --card-bg: rgba(30, 41, 59, 0.8);
    --card-border: rgba(71, 85, 105, 0.5);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --transition: all 0.3s ease;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, var(--bg-primary) 0%, #1e1b4b 50%, var(--bg-primary) 100%);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
    position: relative;
}

/* 动态背景效果 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 80%, rgba(236, 72, 153, 0.1) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
    animation: backgroundFloat 20s ease-in-out infinite;
}

@keyframes backgroundFloat {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    33% { transform: translateY(-20px) rotate(1deg); }
    66% { transform: translateY(10px) rotate(-1deg); }
}

/* 容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* 导航栏 */
header {
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--card-border);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: var(--transition);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    transition: var(--transition);
}

.logo:hover {
    transform: scale(1.05);
}

/* 桌面导航 */
.desktop-nav ul {
    display: flex;
    list-style: none;
    gap: 1.5rem;
}

.desktop-nav ul li a {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.desktop-nav ul li a:hover {
    color: var(--primary-color);
}

.desktop-nav ul li a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transition: var(--transition);
}

.desktop-nav ul li a:hover::after {
    width: 100%;
}

.desktop-nav ul li a.active {
    color: var(--primary-color);
}

.desktop-nav ul li a.active::after {
    width: 100%;
}

/* 移动导航按钮 */
.mobile-menu-btn {
    display: none;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.mobile-menu-btn:hover {
    background: var(--bg-secondary);
}

/* 移动导航 */
.mobile-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    z-index: 2000;
    transform: translateX(-100%);
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.mobile-nav.active {
    transform: translateX(0);
}

.mobile-nav ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    text-align: center;
}

.mobile-nav ul li a {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 1.25rem;
    font-weight: 500;
    transition: var(--transition);
}

.mobile-nav ul li a:hover {
    color: var(--primary-color);
    transform: scale(1.1);
}

.mobile-nav ul li a.active {
    color: var(--primary-color);
}

@media (max-width: 768px) {
    .desktop-nav {
        display: none;
    }
    
    .mobile-menu-btn {
        display: block;
    }
}

/* 卡片样式 */
.card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color), var(--accent-color));
    transform: scaleX(0);
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-color);
}

.card:hover::before {
    transform: scaleX(1);
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
    border: none;
    font-size: 0.95rem;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: var(--transition);
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--card-border);
}

.btn-secondary:hover {
    background: var(--secondary-color);
    border-color: var(--secondary-color);
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.btn-outline:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

/* 表单控件 */
select, input, textarea {
    background: var(--bg-secondary);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-md);
    padding: 0.75rem 1rem;
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: var(--transition);
    width: 100%;
}

select:focus, input:focus, textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

select:hover, input:hover, textarea:hover {
    border-color: var(--secondary-color);
}

/* 标题 */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 {
    font-size: 2.5rem;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h2 {
    font-size: 2rem;
    color: var(--text-primary);
}

h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
}

h4 {
    font-size: 1.25rem;
    color: var(--text-primary);
}

/* 段落和文本 */
p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

/* Hero 区域 */
.hero {
    padding: 4rem 0;
    text-align: center;
    margin-bottom: 4rem;
}

.hero h1 {
    margin-bottom: 1.5rem;
}

.hero h2 {
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 2.5rem;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* 首页特性部分 */
.features {
    padding: 4rem 0;
    margin-bottom: 4rem;
}

.features h2 {
    text-align: center;
    margin-bottom: 3rem;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color), var(--accent-color));
    transform: scaleX(0);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-color);
}

.feature-card:hover::before {
    transform: scaleX(1);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.5rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
    transition: var(--transition);
}

.feature-card:hover .feature-icon {
    transform: scale(1.1);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

.feature-card h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.feature-card p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
}

/* 首页统计部分 */
.stats {
    padding: 4rem 0;
    margin-bottom: 4rem;
}

.stats h2 {
    text-align: center;
    margin-bottom: 3rem;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.stat-card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transform: scaleX(0);
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-color);
}

.stat-card:hover::before {
    transform: scaleX(1);
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    display: block;
}

.stat-label {
    font-size: 1rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* 测试区域 */
.test-section {
    padding: 3rem 0;
}

.test-header {
    margin-bottom: 2rem;
}

.test-controls {
    margin-bottom: 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    align-items: end;
}

.test-controls .form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.test-controls label {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* 测试区域 */
.test-area {
    margin-bottom: 2rem;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
}

/* 反应测试 */
.reaction-area {
    width: 100%;
    height: 800px;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    border: 2px dashed var(--card-border);
    position: relative;
    overflow: hidden;
}

/* Fullscreen reaction area */
.reaction-area.fullscreen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 1000;
    border-radius: 0;
    border: none;
    background: var(--bg-primary);
}

.reaction-area:hover {
    border-color: var(--primary-color);
    background: var(--bg-tertiary);
}

.reaction-area.active {
    background: var(--success-color);
    border-color: var(--success-color);
    cursor: pointer;
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
}

/* 打字测试 */
.typing-area {
    width: 100%;
    margin-bottom: 1.5rem;
}

.text-display {
    font-size: 1.25rem;
    line-height: 1.8;
    margin-bottom: 1.5rem;
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    min-height: 120px;
    border: 1px solid var(--card-border);
}

.text-display span {
    transition: var(--transition);
}

.text-display span.correct {
    color: var(--success-color);
}

.text-display span.incorrect {
    color: var(--error-color);
    text-decoration: underline;
}

.text-display span.current {
    border-bottom: 2px solid var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

.typing-input {
    font-size: 1.25rem;
    padding: 1rem;
    resize: none;
    font-family: 'Courier New', monospace;
}

/* 点击速度测试 */
.click-area {
    width: 100%;
    height: 300px;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    border: 2px dashed var(--card-border);
    position: relative;
}

.click-area:hover {
    border-color: var(--primary-color);
    background: var(--bg-tertiary);
}

.click-target {
    width: 100px;
    height: 100px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.click-target:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.5);
}

.click-target.clicked {
    transform: scale(0.9);
    background: var(--success-color);
}

/* 结果区域 */
.results {
    margin-top: 2rem;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.result-item {
    text-align: center;
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--card-border);
    transition: var(--transition);
}

.result-item:hover {
    transform: translateY(-3px);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

.result-item .value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    display: block;
    margin-bottom: 0.5rem;
}

.result-item .label {
    font-size: 0.9rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* 挑战页面 */
.challenges-section {
    padding: 3rem 0;
}

.challenges-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.challenge-card {
    transition: var(--transition);
}

.challenge-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.challenge-header h3 {
    margin-bottom: 0;
}

.challenge-difficulty {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.challenge-difficulty.easy {
    background: rgba(16, 185, 129, 0.2);
    color: var(--success-color);
}

.challenge-difficulty.medium {
    background: rgba(245, 158, 11, 0.2);
    color: var(--warning-color);
}

.challenge-difficulty.hard {
    background: rgba(239, 68, 68, 0.2);
    color: var(--error-color);
}

.challenge-description {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
}

.challenge-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* 排行榜 */
.leaderboard-section {
    margin-bottom: 3rem;
}

.leaderboard {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--card-border);
}

.leaderboard th, .leaderboard td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--card-border);
}

.leaderboard th {
    background: var(--bg-tertiary);
    font-weight: 600;
    color: var(--text-primary);
}

.leaderboard tr:last-child td {
    border-bottom: none;
}

.leaderboard tr:hover {
    background: var(--bg-tertiary);
}

/* 成就页面 */
.achievements-section {
    padding: 3rem 0;
}

.achievements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.achievement-card {
    text-align: center;
    transition: var(--transition);
}

.achievement-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
    transition: var(--transition);
}

.achievement-card:hover .achievement-icon {
    transform: scale(1.1) rotate(5deg);
}

.achievement-card.unlocked {
    opacity: 1;
}

.achievement-card.locked {
    opacity: 0.5;
    filter: grayscale(1);
}

/* 设置页面 */
.settings-section {
    padding: 3rem 0;
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.settings-card-header {
    margin-bottom: 1.5rem;
}

.settings-card-header h3 {
    margin-bottom: 0.5rem;
}

.settings-card-header p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0;
}

.setting-item {
    margin-bottom: 1.5rem;
}

.setting-item:last-child {
    margin-bottom: 0;
}

.setting-label {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.setting-description {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

/* 关于页面 */
.about-section {
    padding: 3rem 0;
}

.about-content {
    margin-bottom: 3rem;
}

.about-intro {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
    margin-bottom: 3rem;
}

@media (max-width: 768px) {
    .about-intro {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

.intro-text h3 {
    margin-bottom: 1rem;
}

.intro-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.intro-image i {
    font-size: 8rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.feature-item {
    text-align: center;
    transition: var(--transition);
}

.feature-item i {
    font-size: 3rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1rem;
}

.how-it-works {
    margin-bottom: 3rem;
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.step-item {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.step-number {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    flex-shrink: 0;
}

.faq-section {
    margin-bottom: 3rem;
}

.faq-items {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-top: 2rem;
}

.faq-item {
    transition: var(--transition);
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-weight: 600;
    margin-bottom: 1rem;
}

.faq-question i {
    transition: var(--transition);
}

.faq-question.active i {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: var(--transition);
}

.faq-answer.active {
    max-height: 200px;
}

/* 联系部分 */
.contact-section {
    text-align: center;
    padding: 4rem 0;
}

.contact-section .card {
    text-align: left;
    max-width: 900px;
    margin: 0 auto;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-top: 2rem;
}

.contact-form h3,
.contact-info h3 {
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    color: var(--text-primary);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--card-border);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(var(--primary-color-rgb), 0.2);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    transition: var(--transition);
    border: 1px solid var(--card-border);
    text-decoration: none;
    color: var(--text-primary);
}

.contact-link:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: var(--text-white);
    transform: translateY(-2px);
    text-decoration: none;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .contact-content {
        grid-template-columns: 1fr;
    }
}

/* 页脚 */
footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--card-border);
    padding: 3rem 0 1.5rem;
    margin-top: 5rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-section h3 {
    margin-bottom: 1.5rem;
    font-size: 1.25rem;
}

.footer-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.footer-links a {
    color: var(--text-secondary);
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--primary-color);
    padding-left: 0.5rem;
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--bg-secondary);
    border-radius: 50%;
    color: var(--text-primary);
    transition: var(--transition);
    border: 1px solid var(--card-border);
}

.social-links a:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
    transform: translateY(-3px);
}

.footer-bottom {
    text-align: center;
    padding-top: 1.5rem;
    border-top: 1px solid var(--card-border);
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .card {
        padding: 1.5rem;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1.1rem;
    }
    
    .test-section, .challenges-section, .settings-section, .about-section {
        padding: 2rem 0;
    }
    
    .results-grid, .challenges-grid, .achievements-grid, .settings-grid, .features-grid, .steps-grid {
        grid-template-columns: 1fr;
    }
}

/* 加载动画 */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(99, 102, 241, 0.3);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* 成功/错误消息 */
.message {
    padding: 1rem 1.5rem;
    border-radius: var(--radius-md);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.message-success {
    background: rgba(16, 185, 129, 0.2);
    border-left: 4px solid var(--success-color);
    color: var(--success-color);
}

.message-error {
    background: rgba(239, 68, 68, 0.2);
    border-left: 4px solid var(--error-color);
    color: var(--error-color);
}

.message-warning {
    background: rgba(245, 158, 11, 0.2);
    border-left: 4px solid var(--warning-color);
    color: var(--warning-color);
}

.message-info {
    background: rgba(99, 102, 241, 0.2);
    border-left: 4px solid var(--primary-color);
    color: var(--primary-color);
}